Tensioning means for web rolls and other materials



May 22, 1923. 1,455,976

w. c. STEVENS TENSIONING MEANS FOR WEB ROLLS AND OTHER MATERIALS FiledMay 1, 1920 am/v/w YM Q. 5 My Patented May 22, 1923.

UNITED STATES PATENT OFFICE.

WILLIAM C. STEVENS, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUTLER.-HAMMER MFG. CO., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WIS- CONSIN.

TENSIONING MEANS FOR WEB ROLLS AND OTHER MATERIALS.

Application filed- Kay 1,

To all whom it may concern:

Be it known that 1, WILLIAM C. S'rnvnns, a citizen of the United States,residing at Milwaukee, in the county of Milwaukee and State ofWisconsin, have invented new and useful Improvements in Tensioning Meansfor Web Rolls and Other Materials, of which the following is a full,clear, concise, and exact description, reference being had to theaccompanying drawing, forming a part of this specification.

This invention relates to tensioning means for web rolls and othermaterials.

As it is understood, it is desired to maintain rinting press webs underconstant tension in feeding the same to a rem and also inwinding the webfor use. owever, great difliculty has been experienced in maintainingconstant tension either in unwinding or winding due to the variations indiameter of the roll and other variable conditions met with in practice.

It has heretofore been proposed to effect proper tensioning of the webby supporting the same upon rollers, driving the rollers in the samedirection but at slightly different speeds to effect a drive of the webroll and to exert a drag on the web, and varying the speed ratio of therollers to compensate for variations in the diameter and weight of theweb roll. Such means, however, have proven unsatisfactory for unwindinand only partly successful for winding ue in part to the fact that thedrag which it is desired to regulate does not in general vary directlywith the relative speeds of the parts which are in frictional contactand in part to inherent characteristics of the means employed forvarying and controlling the relative speed of the rollers.

The present invention has among its objects to provide improvedtensioning means of the aforesaid character to maintain under constanttension a printing press web or other material during either unwindingor winding thereof.

Another object is to provide means of the aforesaid charactercontrollable automatically to maintain constant tension.

Other objects and advantages of the invention will hereinafter appear.

According to the present invention it is 1920. Serial No. 378,162.

proposed to employ spaced supports for the roll, said supports preferablcomprising rollers driven at slightly di erent speeds but having aconstant speed ratio variable at will. Further, it is proposed to varythe distance between the supports in such a manner as to compensate forvariations in diameter of the web roll and other variable conditions.With the proposed means the drag effected by the driving roller havingthe lower rotative speed and conse uently the tension upon the web willbe $11 stantially determined by the pressure between and normal to thecoacting surfaces of the web roll and such driving roller. Moreover,this pressure is determined substantially by two oppositely varyingfunctions of the length of radius of the web roll, namely, the weight ofthe web roll which varies proportionately to the square of such radius,and the angle which the direction of such pressure makes with thevertical, which angle increases as the radius of the web roll decreases(amuming a fixed distance between centers of the driving rollers). If,therefore, such distance be so varied that the consequent variation ofsaid angle shall exactly compensate for the concurrent variation inweight of the roll, the effective normal pressure will remain constantand consequently the web tension will likewise remain constant.

The accompanying drawing illustrates schematically and diagrammaticallya preferred means of carrying out the invention and the same will now bedescribed, it being understood that the means illustrated aresusceptible of various modifications.

Referring to the drawing, the same illustrates a roll 1 of web or othermaterial to be supplied to a printing press or other machine representedby a pair of rollers 2, said rollers being utilized to draw the materialfrom its roll. The roll 1 is mounted upon and between a pair a ofsimilar spaced rollers 3 and 4, adapted to be driven by the printingpress mechanism, through similar reductio gear including belts 5 and 6cooperatingwith pairs of cone pulleys 7 and 8 so adjusted that theperipheral speed of c I winding it is of-the roller 4 is maintained at avalueless than that of the roller 3 by a definite ratio, such, forexample as 2%, such ratio, however, being amenable to preselection andadjustment at will. In practice the web is preferably passed beneath andpartly about the roller 3.

Said rollers 3 and 4 are respective] pro vided with supports 9 and 10,the ormer being relatively stationary and the latter being slidable formovement of the roller 4 either toward or away from the roller 3. Ascrew mechanism 11 is provided for efi'ecting such movement of theroller 4, said mechanism being operated at a reduced speed bearing adefinite ratio to the speed of the printing press mechanism throughsuitable reduction gearing including a worm gear indicated at 12, orbeing capable of manual operation if desired.

In practice the driving rollers are initially spaced such a distancebetween een ters as, under the assumed speed ratio, to provide thenecessary or desired tension upon the web, assuming the diameter of theweb roll to be a maximum, the pitch and speed of the screw beingcalculated to advance said movable rollertoward the relatively fixedroller at such speed as to maintain such tension constant duringunwinding of the entire roll.

It has been demonstrated that although in general the curve representinginstantaneous values of the ion th of radius of the web roll and of theistance between centers of the two driving rollers is not entirely plainand regular, nevertheless covering the ranges involved in unwinding theweb from a paper roll of ordinary size and under the conditionsordinarily obtaining in printin press operation, such curve issubstantial y straight, thus indicating that the necessary movement ofthe movable roller is continuous and constant and therefore may besatisfactorily cll'ected by the screw mechanism described.

It has also been demonstrated that for maintaining the web tensionsordinarily employed in printing press operation, the drivin rollers willbe initially spaced a distance su cient to insure against dislodgmentofthe web roll therefrom and said driving rollers will moreover approachone another so closely at the termination of the unwinding of anyindividual roll that the distance between adjacent peripheral ortionsthereof ismateriallv less than the diameter of the core or man rilordinarily employed, thus eliminatin v tically exhauste' roll droppingbetween the driving rollers.

In order to adapt the device to use in merely necessary to adjust theratio of the rollers 3 and 4 by shifting the belts 5 and 6 withreference to their all danger of the prac-' respective cone pulleys insuch a. manner that the peripheral speed of the roller 4 shall equal thelinear velocity of the web to be wound, the speed of the roller 3 beingsufliciently reduced to effect the necessary drag for tensioning thematerial it being further assumed that the rolls in this instanceindicate a feeding device and that therefore the direction of rotationofthe various parts will be the reverse of that heretofore described.

In this operation the supporting rollers 3 and 4 will at first bearranged relatively close together to support the winding mandril andalso to eii'ect the necessary drag thereon, the space between saidrollers being progressively increased to compensate for increase indiameter of the roll, the various parts performing functions similar tothose afore-described but in reverse senses consistently.

Although for ordinary requirements during either unwinding or winding,the aforedescribed progressive regulation of the distance betweencenters of the supporting rollers is fully adequate for maintaining theweb tension constant, nevertheless obviously such action may besupplemented by variation in the speed ratio of said rollers by means ofthe cone pulleys should special circumstances render such actionnecessary or desirable.

In practice a diil'erential gear 13 is pref erably interposed in thedrive of the screw ll, said gear including an element to be directlydriven by the worm gear 12 of the roller driving mechanism, and alsoincluding. an element having a power connection with a reversible motor14 through a second worm gear 15, whereby following either unwinding orwinding of a roll of material said motor may be operated to drive thescrew in the proper direction for positioning the roller 4 in a suitablerelation to receive the next roll.

Here it may be noted that the individual worm gears 12 and 15 serve,when not positively driven, to lock their respective ditl'crential gearelements, whereby rotation of either of said elements during inaction ofthe other is transmitted to the screw 11 without loss due to backrotation of the other element.

To provide for reversal of the motor 14 the same is preferably providedwith oppositely wound fields 16 and 17 while a conventional form ofswitch mechanism indicated at 18 serves to control the motor circuit andto efiect selection between said fields for starting the motor anddetermining the direction of rotation thereof.

In practice the switch mechanism 18 is preferably controllable by atension res onsive device of known construction inc uding a roller 19 tobe raised and lowered in res onse to variations in tension of thematerial and a lever 20 for transmitting such motion to the switchmechanism for effecting operation of the motor in a direction tocompensate for such variation, whereby the operation of the device isrendered fully automatic. An adjustable tension spring 21 serves toprovide for predetermination of the de ree of tension to be maintained.

In the operation of the device, assuming such adjustment of the spring21 that for the desired tension upon the material the switch arm is inthe neutral position illustrated, the desired operation of unwinding orwinding may be at once started without regard to any particular relativepositioning of the rollers 3 and 4. If said rollers are not properlypositioned initially the motor 14 is at once started in the properdirection to bring the, same into suitable relation, and such conditionwhen once established will ordinaril be maintained by the continuousdrive 0 the screw through the worm gear 12 without further action of themotor. Such adjusted settin of the roller 4 will occur automaticallywienever the roll of material is replaced or'upon any other change inoperative conditions which would otherwise cause the tension of thematerial to vary from that predetermined. Also to provide foroperationof the device under conditions which differ widely from thosecontemplated in the design of the primary actuating mechanism for thescrew, the motor may act intermittently in either sense or evencontinuously to eflect the necessary correction, while undercircumstances of sudden and extreme variation in operat ing conditionsthe continuous drive of the screw might even be suspended, the motoralone being relied upon for effecting the necessary movements of theroller 4.

What I claim as new and desire to secure by Letters Patent is:

1. In a device ,for tensioning material as drawn from or wound upon aroll, in combination, spaced supports for such roll, said supports beingrelatively movable for varying that pressure component due .to gravitywhich is normal to the contacting portions of such roll and saidsupports.

2. In a device for tensioning material as drawn from or wound upon aroll, the combination with a pair of s aced supports for such roll forefl'ecting a rag upon thematerial as drawn therefrom or wound thereon,

, of means for effecting translatory relative movement of said supportsproportional'to the rate of travel of the material to be ten,- sioned torender such dragsubstantially constant irrespective of variations insize of such roll.

3. In a device for tensionin material as drawn from or wound upon a r01, the combination with a pair of spaced supports for such roll adaptedto effect a drag upon such material substantialliy determined b thatpressure component no to gravity which is normal to the contactingportions of such roll and said supports, of means for effecting relativemovement of said supports for maintaining such pressure componentsubstantially constant irrespective of variations in diameter and weightof such roll.

4. In a device for tensioning material as drawn from on wound upon aroll, the combination with a pair of spaced supports to receive suchroll thereabove and therebe tween, one of said supports being rotatable,of means for driving said support in synchronism with the material to betensioned for efi'ec'ting a drive of such roll, the other of saidsupports being adapted to exert upon the roll a drag substantiallydetermined by the gravity component of the latter upon the former fortensioning the material, and means for varying the distance between saidsupports to maintainsuch component substantially constant irrespectiveof variations in diameter and weight of such roll.

5. In a device for tensioning material as drawn from or wound upon aroll, the combination with a pair of spaced supports to receive suchroll thereabove and therebetween, one of said supports being rotatable,of means for driving said support in synchronism with the material to betensioned for effecting a drive of such roll, the other of said sup rtsbeing ada ted to exert upon the roll a rag substantia ly determined bythe pressure of the latter upon the former for tensioning the material,and means ,for effecting translatory relative movement of said supportsat a speed bearing a definite ratio to the speed of the material to betensioned for maintaining such pressure substantially constantirrespective of variations in diameter of such roll.

6. In a device for tensioning material as drawn from or wound upon aroll, the combination with common means for supporting and driving suchroll and for tensionin such material, said means includin a ro drivingelement to be driven in syn ronism with the web and a web tensiomngelement to be driven at a lesser speed bearing a definite relation tothe speed of said former element, and means for varying the angularrelation of said latter element to said web roll to compensate forvariations in size of said roll at a rate proportional to the rate oftravel of the web. a

7. In a device ,for tensioning material as drawn from or wound upon aroll, the com: bination with driving means for the roll, of combinedroll sup orting and web tensioning means ada te to exert upon thematemeans, and means for maintainingsuch component substantiallyconstant irres ective of predetermined variations in size 0 said roll.

8. In a tensioning device for material drawn from or wound u on a roll,the combination with a pair 0 spaced rollers for supporting and drivingsuch roll, means for driving said rollers in the same direction atspeeds differing from one another by a definite ratio, and formaintaining the speed of one of said rolls synchronous with the speed ofthe material to be tensioned, of means for automatically andprogressively varying the distance between said rollers at a rateproportional to the rate of travel of the material to compensate forprogressive variations in radius of said roll.

9. In a tensioning device for material drawn from or wound upon a roll,the combination with a pair of spaced rollers for s'upportingand drivingsuch roll, means for driving said rollers at speeds difi'ering from oneanother by a definite ratio and for maintaining the speed of one of saidrolls s nchronous with the speed of the materia to be tensioned, ofmeans for automatically and progressively varying the distance betweensaid rollers to compensate for progressive variations in radius of saidroll and meansfor varying the relative speed of said rollers.

10. In a tensioning device for material drawn from or wound upon a roll,the combination with a pair of spaced rollers for supporting and drivingsuch roll, means for driving said rollers at speeds diifering from oneanother by a definite ratio and for maintaining the speed of one of saidrolls synchronous with the speed of the material to be tensioned, ofmeans for automatically and progressively varying the distance betweensaid rollers to compensate for progressive variations in radius of saidroll', and speed varying means for said rollers for rendering the speedof either of the same selectively synchronous with the speed of thematerials to adapt-the device for service in either unwinding orwinding.

11. 'In' a device for tensloning material as drawn from or wound upon aroll the combination with a pair of spaced supports for such roll forefl'ecting a drag u on th terial as drawn therefrom or wound thereon ofmeans for effecting relative movement oi said supports t a reduced speedbearing a definite relation to the linear velocity of such material, andadditional power means for effecting relative movement of said supports.

12. In a device for tensioning material as drawn from or wound upon aroll the comhination with a pair of spaced supports for such roll foreffecting a drag upon the material as drawn therefrom or wound thereon.of means for effecting relative movement of said supports, additionalpower means for effecting relative movement of said supports and meansresponsive to variations in tension of the material for controlling saidlatter means.

13. In a device for tensioning material as drawn from or wound upon aroll, the comhination with a pair of spaced rollers for supporting anddriving such roll, means for driving said rollers at speeds differing 1"rom one another by a definite ratio and for maintaining the speed of oneof said rolls synchronous with the speed of the mat rial to hetcnsioned, of means for automatically and progressively varying thedistance betwecn said rollers to compensate for progressive variationsin radius of said roll, speed varying means for said rollers forrendering the speed of either of the same selectively synchronous withthe speed of the materials to adapt the device for service in eitherunwinding or winding, and

additional power means for effecting relative movement of said rollersin opposite directions selectively. i

14. In a device for tensioning material as drawn from or wound u on aroll, in combination, a pair-of space supporting rollers for such roll,means for driving said rollers in the same direction at speeds bearing adefinite ratio to one another for driving such roll and exerting a dragupon the material and maintaining the higher of such speeds synchronouswith the speed of the material, means operable for effecting relativemovement of said rollers in opposite directions selectively andassociated sets of operating means for said latter means including adifferential gear having an element to he driven at speeds bearing adefinite ratio to the speed of the material and a second element to beoperated and controlled in response to tension variations .of suchniaterial.

In witness whereof, I have hereunto subscribed my name.

WILLIAM C. STEVENS.

Certificate of Correction.

It is hereby certified am 1 um Patent No. 1 455,976, $31M m 22, 19 3, 7

upon the application of William C. Stevens, of waukoe, moomin, for onimprovement in Tonsioning Means for Web Rolls and Other Materials, onerror appou's in the printed specification requiring correction usfollows Poi: 3, lines 121 and 129, chim 6, strike out the words at arato proportional to t true! of tho web" and insert the some to followthe word .1011 in line 120; and that tho said Letters Potent should berand with this oorrution therein that tho some ma conform to the recordof the case in the Patent OiEoo.

Si aid sealed this 31st day of July, A. 1)., 1923.

[um] KARL FENNING,

Adi-g 0W of P

